Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.ArrayList;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Sanket Makani
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader sc, PrintWriter w) {

            int n = sc.nextInt();
            int m = sc.nextInt();

            int arr[][] = new int[n + 1][m + 1];
            int arr1[][] = new int[n + 1][m + 1];

            for (int i = 1; i <= n; i++) {
                for (int j = 1; j <= m; j++) {
                    arr[i][j] = sc.nextInt();
                    arr1[i][j] = arr[i][j];
                }
            }

            int max_row[] = new int[n + 1];

            Arrays.fill(max_row, Integer.MAX_VALUE);

            for (int i = 1; i <= n; i++) {
                for (int j = 1; j <= m; j++)
                    max_row[i] = Math.min(max_row[i], arr[i][j]);
            }
//        w.println(Arrays.toString(max_row));
            ArrayList<String> list = new ArrayList<String>();

            for (int i = 1; i <= n; i++) {
                if (max_row[i] != 0) {
                    for (int j = 0; j < max_row[i]; j++)
                        list.add("row " + i);

                    for (int j = 1; j <= m; j++)
                        arr[i][j] -= max_row[i];
                }
            }

            int max_col[] = new int[m + 1];

            Arrays.fill(max_col, Integer.MAX_VALUE);

            for (int i = 1; i <= m; i++) {
                for (int j = 1; j <= n; j++)
                    max_col[i] = Math.min(max_col[i], arr[j][i]);
            }

            for (int i = 1; i <= m; i++) {
                if (max_col[i] != 0) {
                    for (int j = 0; j < max_col[i]; j++)
                        list.add("col " + i);

                    for (int j = 1; j <= n; j++)
                        arr[j][i] -= max_col[i];
                }
            }

            int flag = 0;

            for (int i = 1; i <= n; i++) {
                for (int j = 1; j <= m; j++) {
                    if (arr[i][j] != 0)
                        flag++;
                }
            }

            if (flag != 0)
                w.println("-1");
            else {
//            w.println(list.size());
//
//            for(String str:list)
//                w.println(str);

                ArrayList<String> list1 = new ArrayList<>();

                Arrays.fill(max_col, Integer.MAX_VALUE);

                for (int i = 1; i <= m; i++) {
                    for (int j = 1; j <= n; j++)
                        max_col[i] = Math.min(max_col[i], arr1[j][i]);
                }
                for (int i = 1; i <= m; i++) {
                    if (max_col[i] != 0) {
                        for (int j = 0; j < max_col[i]; j++)
                            list1.add("col " + i);

                        for (int j = 1; j <= n; j++)
                            arr1[j][i] -= max_col[i];
                    }
                }

                Arrays.fill(max_row, Integer.MAX_VALUE);

                for (int i = 1; i <= n; i++) {
                    for (int j = 1; j <= m; j++)
                        max_row[i] = Math.min(max_row[i], arr1[i][j]);
                }


                for (int i = 1; i <= n; i++) {
                    if (max_row[i] != 0) {
                        for (int j = 0; j < max_row[i]; j++)
                            list1.add("row " + i);

                        for (int j = 1; j <= m; j++)
                            arr1[i][j] -= max_row[i];
                    }
                }

                flag = 0;

                for (int i = 1; i <= n; i++) {
                    for (int j = 1; j <= m; j++) {
                        if (arr1[i][j] != 0)
                            flag++;
                    }
                }

                if (flag != 0)
                    w.println("-1");
                else {
                    if (list.size() < list1.size()) {
                        w.println(list.size());
                        for (String str : list)
                            w.println(str);
                    } else {
                        w.println(list1.size());
                        for (String str : list1)
                            w.println(str);
                    }
                }
            }
        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1)
                throw new InputMismatchException();

            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }

                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = read();

            while (isSpaceChar(c))
                c = read();

            int sgn = 1;

            if (c == '-') {
                sgn = -1;
                c = read();
            }

            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            }
            while (!isSpaceChar(c));

            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}